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Quartz Dielectric Cathode Ring Improves Etch Rate

IP.com Disclosure Number: IPCOM000039591D
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Seirmarco, JA: AUTHOR [+2]

Abstract

A modification of the material composition of the cathode ring in an etch tool has resulted in an improved etch rate with better uniformity in dry etching of semiconductor wafers. A plasma etch system is used for photoresist (PR) strip of semiconductor wafers and descum, partial photoresist removal, in semiconductor processing. The specific tool being used is a single wafer, cassette-to-cassette etching tool using O2 and radio frequency (RF) plasma. The original system had the lower electrode (cathode) configuration indicated by Fig. 1. The silicon wafer 1 being processed (Image Omitted) rested on the lower RF-powered electrode 2. A pin plate 3 with vertical motion and equipped with lift pins 4 raised the wafer into the plasma chamber 8 or lowered it back into the recess of the electrode.

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Quartz Dielectric Cathode Ring Improves Etch Rate

A modification of the material composition of the cathode ring in an etch tool has resulted in an improved etch rate with better uniformity in dry etching of semiconductor wafers. A plasma etch system is used for photoresist (PR) strip of semiconductor wafers and descum, partial photoresist removal, in semiconductor processing. The specific tool being used is a single wafer, cassette-to-cassette etching tool using O2 and radio frequency (RF) plasma. The original system had the lower electrode (cathode) configuration indicated by Fig. 1. The silicon wafer 1 being processed

(Image Omitted)

rested on the lower RF-powered electrode 2. A pin plate 3 with vertical motion and equipped with lift pins 4 raised the wafer into the plasma chamber 8 or lowered it back into the recess of the electrode. The chamber wall 5 was grounded with a ceramic insulator ring 6 completing the configuration. Descum must be performed with the pins down to meet the required uniformity specification of the production line. With the original configuration, the tool was not meeting the desired descum uniformity. This was primarily because, as shown in Fig. 2, the periphery 9 (outer 1.5 cm) of the wafer 1 etched faster than the rest of the wafer. The PR removed 10 during descum left the PR etch profile 11 (of photoresist remaining after descum) showing excessive etching taking place near the edge of wafer 1. In addition to the difficulty with desc...